BEIJING (AFP) - Two Chinese children were killed and another four injured after a wall at their primary school collapsed, reports said.

The victims, a girl named Wang Yuzhen and a boy named An Zhengguo, both 12, died as they were being taken to hospital in Linkou in Yunnan, according to yunnan.cn.

The news portal, which is run by the south-western province's government, added the other four victims, all fifth-graders at the school, were in stable condition with non-life-threatening injuries.

It quoted a local resident saying the collapse on Wednesday could have been caused by pressure from large stacks of coal that had been piled up against the wall.

Infrastructure problems have become a source of increasing concern in China, where the booming economy has spurred a wave of new construction but where corruption is common and strict enforcement of building codes is often lacking.

School infrastructure has come under particular scrutiny following the deaths of thousands of students in buildings that collapsed during the massive 2008 earthquake that hit Yunnan's neighbouring province of Sichuan.

Many parents at the time blamed poor construction, but their demands for an investigation were ultimately unsuccessful and no one has been prosecuted over the deaths.